Warning: include_once(): Failed opening '/var/www/html/wp-admin/includes/plugin.php' for inclusion (include_path='.:/usr/local/lib/php') in /var/www/html/wp-content/plugins/amazon-s3-and-cloudfront/classes/as3cf-compatibility-check.php on line 135

Fatal error: Uncaught Error: Call to undefined function is_plugin_active() in /var/www/html/wp-content/plugins/amazon-s3-and-cloudfront/classes/as3cf-compatibility-check.php:137 Stack trace: #0 /var/www/html/wp-content/plugins/amazon-s3-and-cloudfront/wordpress-s3.php(52): AS3CF_Compatibility_Check->is_plugin_active('amazon-s3-and-c...') #1 /var/www/html/wp-includes/class-wp-hook.php(292): as3cf_init('') #2 /var/www/html/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters(NULL, Array) #3 /var/www/html/wp-includes/plugin.php(484): WP_Hook->do_action(Array) #4 /var/www/html/wp-settings.php(560): do_action('init') #5 /var/www/html/wp-config.php(103): require_once('/var/www/html/w...') #6 /var/www/html/wp-load.php(37): require_once('/var/www/html/w...') #7 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...') #8 /var/www/html/index.php(17): require('/var/www/html/w...') #9 {main} thrown in /var/www/html/wp-content/plugins/amazon-s3-and-cloudfront/classes/as3cf-compatibility-check.php on line 137